This invention relates to analog reference signal generation for pin drivers and pin sensors of an automated test equipment (ATE) system. More particularly, this invention relates to an apparatus for setting reference voltage levels from memory via a common analog line and common digital to analog converter for multiple pin drivers and pin sensors.
Automated test equipment (ATE) systems are used for testing printed circuit boards or integrated circuits. For either application, test signals are generated at pin drivers, while response signals are sensed at pin sensors. Typically, a pin driver or pin sensor receives analog reference voltage signals for defining a high reference level and a low reference level. Such reference levels are used to define the voltage swing by the pin driver between a logic high output and a logic low output. Such reference levels also are used by pin sensors to define the voltage swing for sensing a logic low and a logic high.
As an ATE has many pin drivers and pin sensors (i.e., one each per pin of a device under test or pin of a PCB), many reference signals are to be defined and coupled to the respective pin drivers and pin sensors. According to a conventional approach, a digital to analog converter is used for each reference signal of each pin driver and each pin sensor. The use of so many DACs creates undesirable expense and requires added space. Accordingly, there is a need to provide a more optimal configuration with fewer DACs.